Book excerpt: Wall Street is where poker and modern finance?and the theory behind these "games"?clash head on. In both worlds, real risk means real money is made or lost in a heart beat, and neither camp is always rational with the risk it takes. As a result, business and financial professionals who want to use poker insights to improve their job performance will find this entertaining book a "must read." So will poker players searching for an edge in applying the insights of risk-takers on Wall Street.